The present invention relates generally to an apparatus for unwinding material from a previously wound roll and, more particularly, to an improved apparatus onto which rolls of sheet form material and the like can be loaded in preparation for unwinding, and then quickly and easily lifted and rotated from a loading position into an unwinding position when a previously loaded roll has been unwound.
Many products are manufactured from elongated sheet or stock material that is shipped and stored in the form of a roll or coil. Continuous strips or webs of thin, flexible material are commonly provided on storage rolls that are subsequently unwound for production of items made from these materials. Examples of these materials are plastic film, metal foil, and paper. Other materials such as cable or wire are also wound onto rolls.
During the manufacture of paper products such as napkins, newspapers, and magazines, for example, very large storage rolls of paper are used to provide the stock material from which the paper items are produced. The storage rolls are then unwound for further processing such as cutting, folding, or printing.
When a roll is being unwound so that the material can be further processed, it is desirable to quickly change to a new roll once the previous roll is spent. However, the large and heavy storage rolls of stock material are difficult to handle. Also, the manufacturing process must be stopped so that the spent roll can be removed and replaced by a new roll. The time spent unloading and reloading the machine results in decreased production of the final product.
A apparatus that accepts subsequent or stand-by rolls of stock material ready for quick movement into an unwinding position is highly desirable because of the savings in time that such a machine can provide. The stand-by roll can be quickly moved into place, and the unwinding and subsequent processes can proceed with minimal interruption.
The placement of a roll of material onto a shaft or spindle, which is then mounted onto a machine for unwinding of the roll, is another time-consuming manufacturing step. The added steps of inserting the shaft into the core of the roll and then removing it when the roll is unwound results in additional time spent setting up the machine, which also decreases productivity. An apparatus machine that can hold and unwind a roll of material without a shaft or spindle would be advantageous as well.
Thus, there continues to be a need for a method and apparatus for unwinding material from a roll that allows the loading of subsequent rolls of material which are then quickly rotated into position for unwinding. Also, there is a need for a method and apparatus that will increase the speed of the unwinding process by eliminating time-consuming steps, thus increasing productivity. The present invention meets these desires.
A roll unwinding apparatus embodying the present invention efficiently performs lifting and turning operations on a roll of material to unwind the material from the roll.
The material on the roll may be a thin flexible web of material such as foil, plastic film, fabric, or paper. Alternatively, the material may be an elongated strip or length of material such as, for example, wire, cable, string, or rope. For simplicity of explanation, references herein to paper as the material on the roll should be construed to include any material capable of being wound onto a roll and subsequently unwound.
The unwinding machine of the present invention comprises a base, a hollow column extending upwardly from the base, and a lift carriage mounted for movement along and around the column. A rotary track is provided around the column proximal to the column""s upper end.
The lift carriage includes a lift arm assembly for supporting and rotatably holding the roll of material. The lift arm assembly includes a pair of vertically oriented, parallel support arms which accept and support the roll of material during the loading and unwinding operations, respectively. The support arms of the pair are movable relative to one another other along a horizontal support arm track. Each support arm of the pair has a lower end for supporting the roll of material and an upper end that rests on a support arm track. A spindle is inwardly located at the lower end of each support arm of the pair for insertion into the core of a roll of material.
In operation, the support arms move away from one another along the horizontal support arm track to accept the core of a roll on the spindles located therebetween. The lift arms are then moved towards one another and the spindles inserted into the core to releasably and rotatably hold the roll between the support arms. The support arms of the lift arm assembly thus support the roll both during the unwind operation and during movement of the roll between the load and unwind positions on the turret.
The lift arm assembly is movable both vertically along the hollow column and rotatably around the column in conjunction with the rotary track. In the preferred embodiment described herein, the lift arm assembly moves between xe2x80x9cloadxe2x80x9d and xe2x80x9cunwindxe2x80x9d positions around the hollow column. The loading and unwinding operations of a given roll take place at these two positions, respectively.
A lift pin is provided within the column. The lift pin, motor driven by a ball screw, moves vertically along the length of the column between the column""s base and the rotary track. The lift pin is operably associated with the lift arm assembly to raise and lower the assembly between these two locations.
The full roll of material is loaded into the lift arm assembly when the assembly is located proximal to the column""s base (the xe2x80x9cloadxe2x80x9d position). The lift arm assembly is then raised by the lift pin to the rotary track and then rotated 180 degrees around the hollow column on the rotary track into the xe2x80x9cunwindxe2x80x9d position, where the roll is then unwound. After the roll is unwound, the lift arm assembly, having the empty core thereon, is rotated 180 degrees back around the hollow column on the rotary track, where it once again engages the lift pin. After engaging the lift pin, the lift arm assembly is then lowered vertically along the column length from the rotary track to the position proximal to the base plate (load position).
The preferred embodiment described herein further comprises a drive motor for turning the roll to unwind the material therefrom once it has been loaded and moved into the unwinding position. The motor, attached to the hollow column, has a drive shaft extending therefrom that is co-axial with the core of the roll of material when the core is located in the unwind position on the column.
The drive shaft is splined to allow for axial translation of the shaft between the drive motor and material core. Such translation allows the shaft to both extend from the motor (to engage the spindle during the unwind operation) and retract from the spindle back to the motor (when moving the roll to or from the unwind location on the turret).
In overall operation, the lift arm assembly is initially placed at the xe2x80x9cloadxe2x80x9d position and the support arms of the lift arm assembly are moved apart to accept placement of a full roll of material therebetween. The support arms are then moved towards one another and the spindles are inserted into the core to releasably and rotatably hold the roll between the support arms. The lift pin then engages the lift arm assembly to lift the assembly vertically from a location proximal to the base plate of the column up to the rotary track, located proximal to the column""s upper end. Upon reaching the rotary track, the lift arm assembly is then rotated 180 degrees around the column on the rotary track to the xe2x80x9cunwindxe2x80x9d position.
Once the lift arm assembly, having the full roll loaded thereon, is placed in the xe2x80x9cunwindxe2x80x9d position, the splined drive shaft is axially extended from the drive motor to the spindle which has been inserted into the core. Upon engaging the spindle, the drive motor is started for rotation of the roll during the unwind operation. After all material has been unwound from the roll, the drive shaft is disengaged from the spindle and retracted back to the motor. The lift arm assembly, holding the empty core thereon, is rotated back 180 degrees on the rotary track of the column to the lift pin.
Upon engaging the lift pin, the lift arm assembly is then lowered from the rotary track back to the xe2x80x9cloadxe2x80x9d position, proximal to the column""s base plate. The support arms of the lift arm assembly are them moved apart from one another and the empty core removed from therebetween. A full roll of material is then placed between the support arms of the lift arm assembly. The lift arm assembly is then moved again to the unwind position, via the lift pin and rotary track, where the unwind operation is repeated.
More than one lift arm assembly may be provided in the preferred embodiment of the present invention. When additional lift arm assemblies are provided, a subsequent roll (or rolls) can be loaded onto the machine in advance of being unwound. While a roll is in the process of being unwound in the xe2x80x9cunwindxe2x80x9d position on the column, a subsequent, full roll can be loaded onto the machine in the xe2x80x9cloadxe2x80x9d position, and held there until the roll located in the xe2x80x9cunwindxe2x80x9d position is fully unwound.
The subsequent, full roll is then moved from the xe2x80x9cloadxe2x80x9d position to the rotary track via the lift pin. Upon reaching the rotary track, the lift arm assemblies, holding the full roll and the empty core, respectively, are each rotated around the column so that the full roll is moved into the xe2x80x9cunwindxe2x80x9d position from the lift pin while the empty core is moved from the xe2x80x9cunwindxe2x80x9d position and into engagement with the lift pin. The unwinding of the full roll can thus commence while the lift pin lowers the empty core towards the column""s xe2x80x9cloadxe2x80x9d position (for subsequent replacement with another full roll).
There are other advantages and features of the present invention which will be more readily apparent from the following detailed description of the preferred embodiment of the invention, the drawings, and the appended claims.